Advanced nuclear reactors being developed include liquid metal nuclear reactors which use liquid sodium, for example, for cooling the reactor core thereof. In order to circulate the liquid sodium through the reactor core, electromagnetic pumps are used which magnetically pump the liquid sodium therethrough.
More specifically, annular linear induction, or electromagnetic, pumps (ALIP) are known to include annular electrical coils and lamination rings which are stacked together on a common longitudinal centerline axis and have an annular duct extending therethrough. Electrical current provided to the coils induces magnetic flux for pumping the liquid metal through the duct. The coils may be arranged in a singular tubular configuration conventionally known as a single stator electromagnetic pump, or two groups of coils may be used, with the first group being configured in one tubular configuration as a radially inner stator, and the second group configured in another tubular configuration as a radially outer stator spaced radially outwardly from the inner stator to define a concentric annular flow duct therebetween in which the liquid sodium is propelled linearly through the electromagnetic pump parallel to its longitudinal centerline axis.
The liquid sodium is pumped axially through the pump from its bottom inlet to its top outlet, or discharge plenum, wherein it turns radially outwardly away from the centerline axis of the pump. The stator coils of the pump are provided with electrical current through power leads which, in a single stator ALIP, are typically channeled downwardly through the discharge plenum and into the stator. In order to protect the power leads from the liquid sodium in the discharge plenum, suitable conduits, including bellows, surround the power leads and are therefore subject to flow induced vibration and provide a potential sodium leakage path in the event of damage thereto.
Similarly, the power leads to the outer stator of a double stator ALIP may also be disposed in protective conduits, including bellows, where the power leads pass through the discharge plenum. In the double stator ALIP design, however, the power leads to the inner stator may be routed directly from a junction box extending upwardly from the inner stator along the pump centerline axis and disposed radially inside the discharge plenum.
Accordingly, the inner stator power leads are inherently protected by the junction box and not exposed to the liquid sodium, whereas the outer stator power leads must still be protected by separate conduits and bellows, the elimination of which is desired.